The present invention relates generally to fasteners and is more particularly concerned with fasteners adapted for joining a structural member such as a rafter, post, wire tie downs or the like to concrete, masonry or the like.
In the building trades, it is oftentimes necessary to form joints between concrete or masonry foundations or walls and other structural members such as wooden or metal posts, rafters, sill plates, girders, beams, wire tie downs and the like. Many different specialized means have been devised over the years to accomplish each type of such joints. For example, in joining wooden support posts to concrete foundations, common practice has been to simply embed the post into the concrete while the concrete is wet and then allow the concrete to cure or set about the post. A significant disadvantage of this practice is that the embedded portion of the post tends to rot over a period of time due to entrained moisture.
Another means for joining wooden posts such as carport or deck supports to concrete is to use an embedded J-bolt in the concrete which retains a rather thin, square metal cup which is then nailed to the encapsulated post. This type of fastening means has a definite structural weakness in that the shear or pullout strength of the nails is very low compared to that of the J-bolt, the square cup, or the post. In addition, other disadvantages of a J-bolt-square cup fastening means for joining a post to concrete are that a different sized cup is required for each size of post such as 4.times.4 or 6.times.6 and, for many sized posts, a corresponding cup is not presently commercially available. A further disadvantage of the J-bolt-square cup fastening means is that it can be used only for wooden posts and not for metal posts, or sheet metal outbuildings.
In mounting or joining wooden rafters to masonry walls such as in attaching a wooden deck to the existing masonry wall of a house, a header is nailed or bolted to the masonry with the aid of lead anchors set into drilled holes and then the rafters nailed to the header. This approach is oftentimes unsatisfactory as the masonry can be damaged while attaching the header and the strength of the joint may be limited to the pull strength of the nails.
While the above means and methods for joining structural members to concrete or masonry are in primary use today, the patent literature includes many other types of fasteners for the above purposes which, for various reasons, have not found wide acceptability. For example, in U.S. Pat. No. 927,563 to Londelius, a brick anchor comprising a flat elongated steel bar having two holes near one end, one hole near the other end and a round rod projecting through the latter hole is disclosed. U.S. Pat. No. 1,428,327 to Girolami discloses an anchoring or securing device of a generally flat metal body having projecting portions at one end and an enlarged, chisel-like portion at the other end which has an opening therethrough. In U.S. Pat. No. 1,880,709 to Bitney, taught is an anchor for concrete comprising a plate-like body with oppositely disposed flanges on the longitudinal edges each having recessed portions, the body having a hole near each end.
U.S. Pat. No. 1,989,811 to Kulp discloses a concrete insert anchor of sheet metal having a hole near one end and lateral inwardly and downwardly curved edge faces, the anchor having a plurality of corrugations across the major surfaces. The anchor inserts as taught by the U.S. Pat. No. 2,006,300 to Kinninger are of planar sheet metal and include two holes near the center of the inserts and a series of recessed portions along the lateral surfaces of the insert. U.S. Pat. No. 3,750,360 to Kingston discloses an anchor device for securing a wood sill plate to a masonry foundation. In the embodiment shown in FIG. 1 of the Kingston patent, a portion of the U-shaped anchor device comprises a flat elongated member having small recessed portions along the lateral edges and a plurality of holes near both ends of the member.
These known fastening means for joining a structural member to concrete or masonry disclosed in the patent literature as well as those discussed previously suffer from one or more disadvantages such as complicated and expensive manufacture of the fastener, the fastener usefulness is limited to particular applications, insufficient strength of the joint formed by the fasteners, inability to join structural members of varying types, poor anchoring or retention characteristics in concrete or masonry and the necessity for a plurality of components in the fastening means which complicates assembly and increases the cost of the fastening means.